Question

Question: i got this homework problem that can not figure outany help would be appreciatedBalance a 55-kVA-power load at 240 volt 3-phase a power factor of 90% and a 70 kW load at 120/240 volt single-phase at a power factor of 1.0 on a 120/240-volt three-phase, 4-wire service.A = _______ ampereB = _______ ampereC = _______ ampereN = _______ ampereBest regardsHP

Answer 1

Step 1: Convert the 3-phase load to single-phase equivalent

The 55 kVA load at 240 V and 90% power factor has a single-phase equivalent of:

Power = 55 kVA  0.9 = 49.5 kWVoltage = 240 VCurrent = Power / Voltage = 49.5 kW / 240 V = 206.25 A

Step 2: Calculate the current for the 3-phase balanced load

Since the 3-phase load is balanced, the current in each phase is equal to:
A = B = C = Current / sqrt(3) = 206.25 A / 1.732 = 118.32 A
Step 3: Calculate the current in the neutral wire

The current in the neutral wire is equal to the sum of the currents in the three phases:
N = A + B + C = 118.32 A + 118.32 A + 118.32 A = 354.96 A
Step 4: Calculate the current for the single-phase load

The 70 kW load at 120/240 V and 1.0 power factor has a current of:
Power = 70 kWVoltage = 240 VCurrent = Power / Voltage = 70 kW / 240 V = 291.67 A
Therefore, the balanced currents are: A = 118.32 A B = 118.32 A C = 118.32 A* N = 354.96 A Flag for review

Answer 2

Step 1: Convert the 3-phase load to single-phase equivalent

The 55 kVA load at 240 V and 90% power factor has a single-phase equivalent of:

Topic: help with calculation